1. Technical Field
The present invention relates in general to graphics rendering in data processing systems and in particular to polygon processing to generate primitives during graphics rendering. Still more particularly, the present invention relates to converting general polygons to trapezoidal primitives which a display adapter within a data processing system is capable of rendering.
2. Description of the Related Art
Data processing systems commonly include graphics adapters (also referred to as "display adapters") which receive primitives (e.g., points, lines, or polygons) from the processor for rendering, the process of generating pixel information for a display. The processor may thus write certain, simple primitives to the graphics adapter, which breaks the primitive into scan lines and renders the pixels within each scan line, thereby shifting the overhead associated with breaking the primitive into scan lines and freeing the processor to execute other tasks.
While most contemporary graphics adapters support primitives which are triangles or trapezoids, other polygons, including general polygons, are typically broken into scan lines by the display engine for the operating system or an application, and the scan lines are then sent to the graphics adapter. This consumes processor cycles and may leave the graphics adapter idle, negating the benefits of having a graphics adapter within the data processing system.
It would be desirable, therefore, to provide a mechanism for sending general polygons to a display adapter for rendering.